The available projects are designed to introduce students to standard cleanroom-based fabrication/processing methods (photolithography, materials deposition, surface analysis), optical spectroscopy (Raman, PL), various advanced imaging techniques (scanning electron microscopy, atomic force microscopy, focussed ion beam, transmission electron microscopy) as well as other optical and electronic material/device characterization techniques.
If you are interested in completing one of the MSc projects presented below – please contact Prof. Sakellaris Mailis ().
Background:
Two-dimensional transition metal dichalcogenides (2D-TMDCs) semiconductors are good absorbers for electromagnetic wave radiation in different spectral regions, making them potential candidates for energy harvesting and optical signal detection applications. Nevertheless, using 2D-TMDCs in solar cells and optical communications are currently impeded because of limited broadband responsivity and relatively slow temporal response. These challenges can be readily tackled through alloying of these materials to engineer their bandgaps for ameliorating photo-detection performance. Additionally, integrating 2D-TMDCs alloy with mature silicon technology through local or global solution-based synthesis on silicon wafers is a step further towards realisation of 2D/3D devices.
In this project, we propose a liquid-phase deposition approach for synthesizing n-type 2D-TMDCs alloy films on p-type silicon for direct formation of large area p-n photodiodes. This work will be conducted experimentally in two steps. First, critical growth parameters will be examined through a wide range of microscopic and spectroscopic characterization techniques to assess the quality of the deposited films. Secondly, photoelectric performance of fabricated heterojunction photo-detecting devices will be evaluated.
Learning Outcome:
By the end of the project the student will be able to:
- Knowledge: discuss the Physics of 2D semiconductor materials, discuss the dynamics of thermal dissociation of chemical precursors, discuss the Physics of semiconductor heterostructures.
- Skills: Employ data acquisition methods, extract and analyse experimental data, perform basic cleanroom processes, build and optimize complex optical and electrical experimental arrangements, present research results.
- Experience: Employ standard cleanroom processes, use advanced spectroscopic and imaging tools, compose and present scientific reports.
Background:
In modern life, the increasing amount of harmful and toxic gases emitted by human activities, especially the industrial ones, becomes a global challenge that needs to be urgently addressed. Hence, designing and manufacturing highly efficient sensors is vital to detect, monitor and control these gases. 2D materials offer an exceptional opportunity to build such kind of gas sensors privileging from their extremely high surface to volume ratio along with adsorption-dependent electronic properties.
This project aims to explore the possibility of fabrication and characterisation of highly-dense semiconductor gas sensor arrays by direct laser writing of TMDCs. This synthesis technique is very promising for gas sensing applications where various TMDC members and their alloys; configurations; geometries and layer number can be manufactured within micro-scale precision on single micro-chip. Importantly, as the sulphur vacancies are the main active sites for gas sensing which their density can be modulated by laser irradiation, the sensitivity and other device parameters can be tuned readily by controlling laser synthesis conditions to achieve optimum sensing performance.
Learning Outcome:
By the end of the project the student will be able to:
- Knowledge: discuss the Physics of 2D semiconductor materials, Discuss the physics behind chemical sensors, discuss the dynamics of thermal dissociation of chemical precursors, discuss the Physics of Gaussian beam propagation, focussing and laser imaging.
- Skills: Employ data acquisition methods, extract and analyse experimental data, perform basic cleanroom processes, build and optimize complex optical and electrical experimental arrangements, present research results.
- Experience: Employ standard cleanroom processes, use advanced spectroscopic and imaging tools, utilize sensor testing techniques, compose and present scientific reports